<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
      //实现trim(str)方法，过滤字符串首位空白
      function trim(str) {
        const reg = /(^\s*)|(\s*$)/;
        return str.replace(reg,'');
      }
      const s = " sdsds ";
      console.log(s);
      console.log(trim(s));
    </script>
  </body>
</html>
